Leetcode 442. Find All Duplicates in an Array

Given an array of length n with values in [1,n] where each value appears once or twice, return all values that appear twice in O(n) time and O(1) extra space. The core challenge is to detect duplicates by using the input array itself as bookkeeping (mapping values to indices) rather than extra data structures.

Question Timeline

See when this question was last asked and where, including any notes left by other candidates.

Company

Level

Region

Comments

Your account is free and you can post anonymously if you choose.

Hello Interview Premium

Recent interview questions

System Design Guided Practice

Exclusive content

Learn More

Leetcode 442. Find All Duplicates in an Array

Question Timeline

Comments

Questions

Learn

Links

Legal

Contact